Some of the more frequent causes of microscopic hematuria are:

• Urinary tract infection which may have no apparent symptoms or may cause a persistent urge to urinate, pain or burning during urination, or a strong urinary odor
• Kidney infection (pyelonephritis) which may cause a fever or flank pain, in addition to the symptoms of a urinary tract infection
• Kidney stone or bladder stone which occurs when certain substances which are normally dissolved in the urine crystallize in the urinary tract to form small hard particles. The stones may not be associated with symptoms or may be excruciatingly painful if they are moving through the urinary tract or result in a blockage of the tract
• BPH (benign prostatic hypertrophy) which is a non-cancerous enlarged prostate
• Kidney diseases in general may result in blood cell leakage into the urine
• Cancer of the kidney, bladder, or prostate
• Vigorous exercise, especially distance runners may experience microscopic hematuria
• Other causes include certain inherited disorders, traumatic kidney injuries, and certain medications like blood thinners or arthritis pain relievers 

Risk factors for microscopic hematuria may include:

• Male sex and increased age — men over 50 often have BPH (enlarged prostate)
• Recent infection of the kidney, urinary tract, or prostate
• Family history of kidney disease
• Medications like blood thinners or arthritis pain relievers
• Vigorous exercise, especially distance runners

AUCNY urologists may use a combination of methods to determine the specific cause:

• Detailed history and physical examination – requesting details about symptoms, personal and family medical history, social history including smoking habits, physical examination of the body with special emphasis on the bladder area including rectal/pelvic exam
• Blood test
• Urine test
• Imaging procedures (X-ray, CT, MRI, and ultrasound)
• Cystoscopy – a procedure in which a thin “camera” tube is inserted into the urethra for visualization